Aircraft and other passenger transport vehicle seats are often designed to allow passengers to move from a fully seated upright position to a partially or fully reclined position. These seats may allow only a slight backward motion, or they may be seats that are convertible to a bed, i.e., to a substantially flat bed position so that the passenger may lie down. Premium seats for civil aircraft are often equipped with multiple electrical actuators, which allow independent or combined motion of the seat pan and the backrest. In some instances, these seats may also be surrounded by a privacy shell or partition, which allows seat motion and other passenger movement without interrupting the space of the passenger behind.
Commercial and other aircraft are designed to make the maximum use of space. Difficulty sometimes arises when designing and arranging convertible seats so that the minimum amount of space is used to accommodate each passenger, while still providing the maximum amount of comfort possible. Accordingly, improved seats that convert between an upright and a generally flat, resting position are needed. Additionally, in order to accommodate curved seat back paths, curved privacy shells may be required. However, this solution often requires (and wastes) precious space. Accordingly, improved seats that have a generally flat backrest that can be used with a linear or straight privacy shell, but that can also convert as described above as also needed. Finally, weight, space, and maintenance considerations are always at the forefront of considerations for airlines, and thus, improved seat designs that use fewer components, weigh less, and require less maintenance are also desired.